Zero-point clamping device

Abstract

A zero-point clamping device for centered locking of an object with repeat accuracy, the device comprising: a housing, a receiving opening worked into the housing having a centering axis, at least two clamping slides mounted axially displaceably in a bore provided in the housing, and an actuating element for moving the clamping slides, one axis of rotation of the actuating element running tangentially and at a distance from the receiving opening to enable a reliable, permanent and repeatable fixing of a large number of workpieces and being extremely compact. This is achieved with two spaced-apart threads incorporated in the actuating element, the respective threads of which have identical pitches and are inclined in opposite directions, and a drive pin inserted in each thread in a driving connection with the thread such that the drive pins can be moved along the axis of rotation of the actuating element.

What is claimed is: 
     
       1. A zero-point clamping device ( 1 ) for centered locking of an object ( 2 ) with repeat accuracy, the zero-point clamping device comprising:
 a housing ( 4 ), 
 a receiving opening ( 5 ) worked into the housing ( 4 ), which has a centering axis ( 6 ) with which the axis of symmetry ( 2 ′ or  3 ′) of the object ( 2 ) or the carrier part ( 3 ) is coaxially aligned during the clamping process, 
 at least two clamping slides ( 7 ,  8  or  9 ), each of which is mounted axially displaceably in a bore ( 10 ) provided in the housing ( 4 ) and which open into the receiving opening ( 5 ) during the clamped condition and thereby act on the object ( 2 ) or the carrier part ( 3 ) and secure the object ( 2 ) or the carrier part ( 3 ), and 
 an actuating element ( 11 ) which is rotatably mounted in the housing ( 4 ) and by means of which the clamping slides ( 7 ,  8 ,  9 ) can be moved, one axis of rotation ( 12 ) of the actuating element ( 11 ) running tangentially and at a distance from the receiving opening ( 5 ), 
 characterized in that, 
 two spaced-apart threads ( 13 ,  14 ) are incorporated in the actuating element ( 11 ), the respective threads ( 13 ,  14 ) of which have identical pitches and are designed to be inclined in opposite directions with respect to one another, 
 a drive pin ( 15 ,  16 ) is inserted in each thread ( 13 ,  14 ), this drive pin ( 15 ,  16 ) being in a driving operative connection with the respective thread ( 13  or  14 ) in such a way that the drive pins ( 15 ,  16 ) can be moved along the axis of rotation ( 12 ) of the actuating element ( 11 ) by means of the rotation of the actuating element ( 11 ), 
 at least two drive segments ( 21 ,  22  or  23 ) are mounted in a floating arrangement in the housing ( 4 ) and extend in an arc around the centering axis ( 6 ) of the receiving opening ( 5 ), and 
 two of the drive segments ( 21 ,  22 ) are coupled in a driving arrangement to the actuating element ( 11 ) via one of the respective drive pins ( 15 ,  16 ), that a respective pivot pin ( 17 ,  18 ) is provided between the two drive segments ( 21 ,  22 ) connected to the actuating element ( 11 ) and the drive segment ( 21 ,  22  or  23 ) arranged adjacent thereto to form a swivel joint, and that each clamping slide ( 7 ,  8 ,  9 ) is connected to one of the drive segments ( 21 ,  22 ,  23 ). 
 
     
     
       2. The clamping device according to  claim 1 ,
 characterized in that, 
 a U-shaped receiving pocket ( 24 ), into which the respective drive segment ( 21 ,  22 ,  23 ) is inserted, is incorporated in the respective clamping slides ( 7 ,  8 ,  9 ). 
 
     
     
       3. The clamping device according to  claim 2 , characterized in that,
 the side wall ( 25 ,  26 ) of the receiving pocket ( 24 ) facing the respective drive segment ( 21 ,  22 ,  23 ) is curved in such a way that the width of the receiving pocket ( 24 ) is smaller in size in the region of a central axis ( 19 ) of the clamping slides ( 7 ,  8 ,  9 ) than in the region of a jacket surface. 
 
     
     
       4. The clamping device according to  claim 1 ,
 characterized in that, 
 the two threads ( 13 ,  14 ) worked in the actuating element ( 11 ) have an identical length and in that the length of the thread ( 13 ,  14 ) defines the movement stroke of the clamping slides ( 7 ,  8 ,  9 ). 
 
     
     
       5. The clamping device according to  claim 4 ,
 characterized in that, 
 the length of the thread ( 13 ,  14 ) corresponds at most to one complete revolution of the actuating element ( 11 ). 
 
     
     
       6. The clamping device according to  claim 1 ,
 characterized in that, 
 the threads ( 13 ,  14 ) have two different inclinations (φ 1 , φ 2 ) relative to the axis of rotation ( 12 ), and in that the inclination (φ 1 ) is associated with the rapid stroke of the clamping slides ( 7 ,  8 ,  9 ) and the inclination (φ 2 ) is associated with the clamping movement of the clamping slides ( 7 ,  8 ,  9 ). 
 
     
     
       7. The clamping device according to  claim 1 ,
 characterized in that, 
 a contact surface ( 27 ) is provided in the housing ( 4 ) for the drive segments ( 21 ,  22 ,  23 ), a width of which is greater in size than a width of the respective drive segments ( 21 ,  22 ,  23 ). 
 
     
     
       8. The clamping device according to  claim 1 ,
 characterized in that, 
 the drive segments ( 21 ,  22 ,  23 ) carry out a pivoting movement about the pivot pins ( 17 ,  18 ) in the direction of the actuating element ( 11 ) during the rotational movement of the actuating element ( 11 ). 
 
     
     
       9. The clamping device according to  claim 1 ,
 characterized in that, 
 the side wall of the receiving opening ( 5 ) in the entrance area has a centering cone ( 28 ), and in that the outer contour of the objects ( 2 ) or carrier parts ( 3 ) to be clamped is adapted to the centering cone ( 28 ). 
 
     
     
       10. The clamping device according to  claim 9 ,
 characterized in that, 
 a clamping surface ( 29 ) which runs at an inclination from the horizontal is provided at the respective free end of the clamping slides ( 7 ,  8 ,  9 ), in that a clamping plane ( 30 ) which interacts with the clamping surface ( 29 ) of the respective clamping slides ( 7 ,  8 ,  9 ) is provided on the object ( 2 ) to be clamped or on the carrier part ( 3 ), and in that the radial advance of the clamping slides ( 7 ,  8 ,  9 ) produces an operative contact between the clamping surfaces ( 29 ) and the clamping plane ( 30 ) in such a way that the object ( 2 ) to be clamped or the carrier part ( 3 ) is pressed into the receiving opening ( 5 ) and is pressed onto the centering cone ( 28 ) in the axial direction. 
 
     
     
       11. The clamping device according to  claim 1 ,
 characterized in that, 
 the clamping slides ( 7 ,  8 ,  9 ) are spaced apart from one another at an identical pitch angle which corresponds to 120°. 
 
     
     
       12. The clamping device according  claim 1 ,
 characterized in that, 
 the clamping slides ( 7 ,  8 ,  9 ) have a central axis ( 19 ) and in that the axis of symmetry ( 34 ) of the respective drive segment ( 21 ,  22 ,  23 ) is arranged in a central region of the central axis ( 19 ) and, during an advance movement, the clamping slide ( 7 ,  8 ,  9 ) is displaced by a distance (Δ 1 , Δ 2 ) relative to the central axis ( 19 ). 
 
     
     
       13. The clamping device according to  claim 1 ,
 characterized in that, 
 the clamping slides ( 7 ,  8 ,  9 ) are held in the bore ( 10 ) in an axially guided manner, and in that the connection between the respective pairs of clamping slides ( 7 ,  8 ,  9 ) and drive segments ( 21 ,  22 ,  23 ) is held in the respective bores ( 10 ) in a position-oriented manner. 
 
     
     
       14. The clamping device according to  claim 1 ,
 characterized in that, 
 the drive pins ( 15 ,  16 ) have three partial sections ( 35 ,  36 ,  37 ) with diameters of different sizes, in that the first partial section ( 35 ) is inserted into the thread ( 13  or  14 ) of the actuating element ( 11 ), in that the second partial section ( 35 ) projects outwards or beyond the other two partial sections adjacent to the second partial section and is mounted axially displaceably in a guide groove ( 20 ) incorporated in the housing ( 4 ), and in that the third section ( 36 ) is connected to the respective drive segment ( 21  or  22 ).